[LARTC] Stealth Router

[LARTC] Stealth Router

[M.F. PSIkappa]

Hi,
in FreeBSD kernel is options that make router stealth, packet passed throw
router have no change in TTL value.
Is a posibility to make similar thing in Linux, I think that in traceroute
isn't this hop, no asteris, no router, no change in TTL, nothing ...?

PSIkappa
psi@atlantis.sk


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Re: [LARTC] Stealth Router

[bert hubert]

On Sat, Mar 24, 2001 at 06:32:04PM +0100, M.F. PSIkappa wrote:
> Hi,
> in FreeBSD kernel is options that make router stealth, packet passed throw
> router have no change in TTL value.
> Is a posibility to make similar thing in Linux, I think that in traceroute
> isn't this hop, no asteris, no router, no change in TTL, nothing ...?

There are multiple ways to achieve this. 

* The Ethernet Frame Diverter which allows you to operate as a transparent
  bridge. The URL is in the HOWTO

* The TTL target in iptables. This allows you to raise the TTL again, so
  nobody might see your router. If you disallow certain ICMP Port
  Unreachable messages, I think your router won't appear in traceroute. You
  need to use proxy arp tricks to draw packets into your router if you want
  it to be totally transparent.

Regards,

bert

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Re: [LARTC] Stealth Router

[bert hubert]

On Sun, Mar 25, 2001 at 11:34:59PM +0300, Konrads Smelkov wrote:

> Can someone be more specific about ttl target? In manual there isn't anything matching TTL... 

It's in the iptables-1.2.1a release:

EXTRA EXTENSIONS
       The  following  extensions  are not included by default in
       the standard distribution.

   ttl
       This module matches the time  to  live  field  in  the  IP
       header.

       --ttl ttl
              Matches the given TTL value.

   TTL
       This  target  is  used to modify the time to live field in
       the IP header.  It is only valid in the mangle table.

       --ttl-set ttl
              Set the TTL to the given value.

       --ttl-dec ttl
              Decrement the TTL by the given value.

       --ttl-inc ttl
              Increment the TTL by the given value.

Regards,

bert

-- 
http://www.PowerDNS.com      Versatile DNS Services  
Trilab                       The Technology People   
'SYN! .. SYN|ACK! .. ACK!' - the mating call of the internet

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